Correspondence •
_AVM
February 5, 2003 CITY OF TIGARD
FILE COPY OREGON
Lewis Chui
LRS Architects, Inc.
1121 SW Salmon, suite 100
Portland, OR 97205
Re: Replacement of Existing Wood Stairways to Steel & Concrete
11905 SW 91 — Buildings 1 — 4 Greenburg Oaks Apartments
BUP2003 -00021
Dear Lewis,
We are in receipt of your request to replace the existing wood stairs with steel
and concrete stairs at the above referenced address. The affected stairs are the
rear stairs of the four (4) buildings that serve as the second required exit from the
third floors. The stairs currently are constructed of wood and are in severe
disrepair and unsafe. The proposal is to replace the wood stairs with the rise and
run the same as the existing stairs, provide handrails and landings within the site
constraints, and adding a layer of 5/8 inch type x gypsum board at the walls of
the exit door to these stairs.
We have visited the site with you, the owner's representative and Brad Kilby with
the Planning Division to review the existing conditions. We concur that the
existing stairs are extremely inadequate and safe exiting is compromised with
their current condition. The proposal to install completely noncombustible stairs,
landings guardrail /handrails will drastically improve the current exiting situation.
Although the new stairs will not meet the strict letter of the code, it is our opinion
that the change from combustible to noncombustible is substantial enough that
the overall increase in safety meets the intent of the code.
Therefore, per your letter and in accordance with OSSC Section 104.2.7,
Modifications, we are granting your request with the following conditions.
Although not adopted, we have used Appendix Chapter 34 as a guide.
1. Because of site constraints the stairs will be replaced in the same location
as the current stairs. The new stairs will be less hazardous than the
current stairs in relation to their proximity to the property lines. This will not
cause the existing building or parts thereof to become more unsafe.
13125 SW Hall Blvd., Tigard, OR 97223 (503) 639 -4171 TDD (503) 684 -2772 :
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2. Site constraints show there are practical difficulties in obtaining the
maximum 8 inch rise for the stairs. We will approve the rise to be a
maximum of 8 1 /2 inches which is the current rise of the stairs. This will not
cause the existing building or parts thereof to become more unsafe.
3. The finish to finish dimensions make it impractical, if not impossible, to
provide a minimum of 30 inches in width for the stairway. The proposal is
to maintain a minimum of 29 inches in width. This will not cause the
existing building or parts thereof to become more unsafe.
4. Special inspection is required for the steel fabrication and welding per
structural notes on Sheet S -1 and OSSC Section 1701.5. Carlson Testing,
Inc. has been identified as the agency that will perform the tests. Reports
of all tests shall be forwarded to Hap Watkins, Inspection Supervisor at
13125 SW Hall Blvd. Any discrepancies shall be brought to the immediate
attention of the contractor for correction.
5. The structural engineer is requiring structural observation after the first
stairway is constructed. These reports shall also be forward to Hap
Watkins at the above address.
6. A copy of the approved plans shall be kept on site at all times and shall be
made available to the City inspectors for inspection purposes.
In our opinion, the replacement of the stairs to noncombustible to the same
standard as the existing stairs does not make the building or exiting system more
unsafe than it was before. We believe that it in fact increases the safety simply by
the fact that the new stairs have far less maintenance, are structurally safer and
provide a greater degree of safety overall than combustible stairs.
If you have any questions regarding this review, please call me at (503) 718-
2448.
Sincerely,
6
Gard Lampella
Building Official
c. Hap Watkins, Supervising Inspector
Brad Kilby, Associate Planner
File
- M E M O R A N D U M •
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To: Gary Lampella, Building Official, City of Tigard ti
13125 SW Hall Blvd, Tigard, OR 97223 (503- 639 -4171 ext 2448)
From: Lewis Chui
Project: Greenburg Oaks Stair Replacement Project number: 202108
Date: Tuesday, July 23, 2002
Re: Modifications from Provisions of Uniform Building Code
REPLACEMENT OF EXISTING WOOD STAIRWAY BY STEEL STAIRWAY
1997 Uniform Building Code (Structural Specialty Code) Appendix Chapter 34 (Existing
Structures) Section 3407.2 states that "All required stairs shall have a minimum run of 9 inches
and a maximum rise of 8 inches and shall have a minimum width of 30 inches exclusive of
handrails. Every stairway shall have at least one handrail. A landing having a minimum 30 -inch
run in the direction of travel shall be provided at each point of access to the stairway. Exception:
Fire escapes as provided for in this section.
"Exterior stairs shall be of noncombustible construction. Exception: On buildings of Types III, IV
and V construction, provided the exterior stairs are constructed of wood not less than 2 -inch
nominal thickness."
0
The Proposal: The approximate rise and run are 7 -3/4 inches and 8 -1/2 inches respectively. The
stair width is 29 inches exclusive of handrails. The stairway has at least one handrail. The landing
width is 36 inches minimum in the direction of travel. The stair structural members are structural a
steel, and the treads are precast concrete.
Supporting Reasons for the Modifications:
0
Despite the fact that Appendix Chapter 34 is not adopted by the State of Oregon, Section 3407.2
can still be used as a standard reference. ;
N
Section 104.2.7 states that "When there are practical difficulties involved in carrying out the
provisions of this code, the building official may grant modifications for individual cases."
r
The following is a list of supporting reasons for the modifications:
(a) Special individual reason making the strict compliance of the Building Code impractical
• The existing buildings are located close to nearby property lines. This restricts the dimension o
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of each individual run (8 -1/2 inches instead of 9 inches minimum per Section 3407.2.) For the
sake of consistency in materials fabrication, the proposal maintains the average dimensions
of the existing rise and run.
• The clear (finish -to- finish) dimensions between existing wing walls vary from 58 to 60 inches.
This limits the width of stairs (29 inches exclusive of handrails instead of 30 inches per
Section 3407.2.)
• The proposal offers a landing width of 36 inches minimum, 6 inches more than the minimum
•
per Section 3407.2.
(b) Conformance with the Intent and Purpose of the Building Code
• Each stairway is part of the means of egress for the portion of each existing building it serves.
The occupant load for that portion of the building varies from 12 to 30. It serves as a
secondary means of egress in addition to the existing interior stairway in front. It also acts as
an exit discharge. Therefore, it needs to be repaired to provide adequate egress in
compliance with the provisions of the Building Code.
• The proposal maintains the existing locations of the stairways. None of them obstructs
existing exits.
• There is no change in the use or occupancy of the existing buildings.
• The proposal does not alter the existing building height, number of stories and area.
(c) Fire Protection
• This modification does not lessen any fire protection requirements. On the contrary, one -hour
rated wall construction is provided to the end wall (through which the existing doors are
located.) This is achieved by adding one layer of 5/8" exterior gypsum board to that wall. This
increases protection to users of the stairs when there is a fire in the building.
• The majority of the existing wing walls are kept in place as physical barriers that provide
some degree of resistance to the spread of fire from neighboring balconies to the stairways.
• The proposal does not create a fire hazard. Instead, fire risk is reduced. The stairway is of
noncombustible construction (structural steel members with precast concrete treads.) This is
safer than the existing, untreated, sawn lumber construction. It therefore does not create
conditions dangerous to human life.
(d) Structural Integrity
• This modification does not lessen any structural integrity because no significant alteration to
the existing building is proposed.
• No major structural alterations are proposed for the existing buildings so they won't become
structurally unsafe or overloaded.
• The replacement is structurally rigid and safe; it does not create conditions dangerous to
human life.
(e) Improved Design
• The stairways are further away from property lines in most cases, reducing the risk of fire
spread from neighboring properties.
• The existing stairways are deteriorating. The proposed replacement will ensure safety to
stairway users.
• Per Section 3403.2, "additions or alterations shall not be made to an existing building or
structure when such existing building or structure is not in full compliance with the provisions
of this code except when such addition or alteration will result in the existing building or
structure being no more hazardous based on life safety, firesafety and sanitation, than before
such additions or alterations are undertaken." The proposal will only improve the existing
stairways from every perspective.
Conclusion:
The proposed stair replacement will not cause the existing building to become unsafe. Rather, it
improves the degree of exiting safety from fire, life safety, and structural points of view.
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7650 SW Beveland Street, Suite 100
41\if TM RIPPEY Tigard, OR 97223
CONSULTING ENGINEERS Phone: (503) 443
Fax: (503) 443 -3700
August 20, 2003
City of Tigard FILE O
13125 S.W. Hall Boulevard
Tigard, Oregon 97223
Re: Greenburg Oaks Apartments — Building #1 - #4 Exterior Stair Replacement
11905 SW 91rst Ave., Tigard OR
Permit Number: BUP2003 -00021
Project Number: 2177
To Whom It May Concern:
In accordance with the structural observation requirements of the Uniform Building Code,
Section 1702, structural observations for the following area of work were provided by our office.
1. Completed Framing of the New Steel Stairs.
The observed work and approved modifications appeared to be in substantial conformance with
the project documents.
Sincerely,
D,eg
Darron R. Hayden, P.E., S.E.
Principal
DRH /mdg
cc: Lewis Chui, LRS Architects
Tracy Blodgett, Seabold Construction